U.S. Pat. No. 4,797,488 discloses a series of polycyclic imides with affinity for serotonin 1A receptors useful as antipsychotic anxiolytic agents. Among these is the compound decahydro-3-[4-[4-(2-pyrimidinyl)-1-piperazinyl]butyl]-1,5-methano-6,7,9-m etheno-2H-pentaleno[1,2-d]azepine-2,4(3H)-dione of the following formula (I): ##STR1## U.S. Pat. No. 4,824,999 discloses the compound 2,3,3a3b,4,5,6,6a,7,7a-decahydro-4,6,7-metheno-1H-cyclopentao[a]pentalene- 1,3-dicarboxylic acid as an intermediate in the production of the corresponding anhydride from which I is prepared.
U.S. Pat. No. 4,957,913 discloses a method of treatment of rhypertension which involves administration of one of a series of serotoninergic polycyclic imides. One of these imides is decahydro-3-[4-[4-(2-pyrimidinyl)-1-piperazinyl]butyl]-1,5-methano-6,7,9-m etheno-2H-pentaleno[1,2-d]azepine-2,4(3H)-dione (I).